JPH07174601A - Vibrating type measuring instrument - Google Patents

Abstract

PURPOSE:To provide a vibrating type measuring instrument which is constituted in such a way that external vibrations are not propagated to a measuring unit which measures the mass flow rate or density of a fluid to be measured. CONSTITUTION:A mass flowmeter 13 is equipped with the vibrating type measuring unit 22 which measures the Coriolis force proportional to the flow rate of a fluid to be measured. The unit 22 is provided with a sensor tube 25, a pair of exciters 26a and 26b supported by brackets, and pickups 27a and 27b and the tube 25, exciters 26a and 26b, and pickups 27a and 27b are housed in a cylindrical housing case 28. The upper opening of the case 28 is capped with a discoid lid 32. The unit 22 is hung down from the lid 32. A vibration absorbing member 19 which absorbs external vibrations is interposed between the upper opening of the case 28 and step section of the lid 32 so as to flexibly absorb vibrations propagated from the case 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type measuring device,
In particular, the present invention relates to a vibration type measuring device configured so that external vibration does not propagate to a measuring unit that measures the mass flow rate or density of a fluid to be measured.

[0002]

2. Description of the Related Art For example, in a painting line for painting a work conveyed by a conveyor or the like, a painting robot is installed near the conveyor to automatically perform painting work. The painting robot is installed on the trolley of the moving device, and follows the work conveyed by the conveyor to operate the painting gun attached to the end of the arm according to the painting program pre-teached.
Paint the work surface.

When automatically coating with such a coating robot, there is a demand for a constant discharge amount of the coating material sprayed on the surface of the work, that is, for a uniform coating film. It is necessary to control the paint supplied to the gun with higher accuracy.

Therefore, in the coating robot apparatus, a flow meter for measuring the amount of coating material is provided between the coating material supply unit for supplying the coating material and the coating material tube connecting the coating gun provided at the arm tip of the coating robot. The paint delivery pump was controlled based on the measurement signal from the flow meter to adjust the discharge amount of the paint sprayed from the coating gun. As a flow meter, for example, a Coriolis mass flow meter (hereinafter referred to as a “mass flow meter”) that is a vibration measurement device with high measurement accuracy.
Is applied, and the discharge amount of the paint is controlled with higher accuracy.

In this type of mass flow meter, the Coriolis force generated when the sensor tube through which the paint flows is vibrated is proportional to the flow rate, and the action direction of the Coriolis force is opposite between the inflow side and the outflow side of the sensor tube. Therefore, the flow rate is measured from the phase difference. Therefore, in the above mass flowmeter, when external vibration propagates to the sensor tube, noise is generated in the detection signal.Therefore, conventionally, the mass flowmeter is separated from the painting robot to prevent external vibration from being transmitted to the sensor tube. The measurement accuracy of the mass flowmeter was maintained by fixing it on the surface.

[0006]

However, in the coating robot apparatus as described above, since the mass flow meter is provided outside the operation area of the robot so that the sensor tube is not affected by the robot operation, the coating gun and the mass flow rate are reduced. The distance to the meter becomes longer.

In addition, the coating robot is installed on the carriage of the moving device so that it can be moved according to the work transfer. Therefore, the tube connecting the coating gun and mass flow meter is mounted in a slack state so as not to hinder the movement of the robot, which makes the tube extra long and makes it easier to clean when changing colors. Is reduced.

Further, in the coating system using the coating robot, since the color of the paint is changed, a color change valve and a purge unit are arranged between the paint supply unit and the mass flow meter. Therefore, if the tube between the coating gun and the mass flowmeter becomes long, the amount of residual paint in the tube that is purged during color change increases, and the amount of thinner for purging the tube also increases, resulting in waste. Will increase.

Further, since the tube is long, there is a delay between the amount actually sprayed from the coating gun and the measured value, so that the responsiveness of the measured value to the actual flow rate is lowered and the control of the paint supply amount is delayed.

In order to solve each of the problems described above, a mass flow meter is provided on a carriage of a moving device or an arm of a coating robot to shorten the length of the tube connecting the mass flow meter and the coating gun. Then, the vibration caused by the movement or stop of the carriage or the vibration caused by the arm operation acts on the sensor tube of the mass flow meter, and the Coriolis force fluctuates, so that accurate flow rate measurement cannot be performed.

Therefore, an object of the present invention is to provide a mounting structure for a vibration type measuring device which solves the above problems.

[0012]

The invention according to claim 1 is
A measurement unit that vibrates a sensor tube through which a fluid to be measured passes to measure the mass flow rate or density of the fluid to be measured, a support member that supports the measurement unit, and the support member is fitted into an opening to perform the measurement. In a vibration type measuring device having a storage case for storing a unit, a vibration absorbing member for absorbing external vibration is provided between the opening of the storage case and the support member.

According to a second aspect of the invention, a measuring unit for vibrating a sensor tube through which the fluid to be measured passes to measure the mass flow rate or density of the fluid to be measured, a support member for supporting the measuring unit, In a vibration type measuring device having a storage case in which a support member is fitted in the opening and stores the measurement unit, a vibration for absorbing external vibration between the opening of the storage case and the support member. Providing an absorbing member,
The storage case is made of synthetic resin.

[0014]

According to the first aspect of the present invention, the vibration absorbing member for absorbing the external vibration is provided between the opening of the storage case and the supporting member, so that the sensor tube is vibrated and the mass flow rate or density of the fluid to be measured is increased. It is possible to prevent external vibration from propagating to the measurement unit that measures the.

According to a second aspect of the present invention, a vibration absorbing member that absorbs external vibration is provided between the opening of the storage case and the support member, and the storage case is made of synthetic resin. It is possible to improve the vibration damping property and reduce the weight.

[0016]

1 to 4 show a coating robot system to which an embodiment of a vibration measuring apparatus according to the present invention is applied.

In each of the drawings, in the coating robot system, a coating robot 1 is installed on a trolley 3 of a moving device 2, and a work 4 is conveyed by a conveyor device 5 and a coating robot 1 is passed while passing through a coating booth. The painting work is carried out while moving the carriage with the carriage 3.

The conveyor device 5 conveys the work 4 in the X direction at a constant speed, and the moving device 2 moves the carriage 3 in the X direction along the base 6 in synchronization with the conveyor device 5.

The coating robot 1 has a base 7 fixed on a carriage 3, a swivel base 8 swiveling on the base 7, and a first arm 9 supported by a bracket 8a of the swivel base 8.
The second arm 10 extends horizontally from the upper end of the first arm 9, and the coating gun 12 provided on the wrist 11 at the tip of the second arm 10. The painting robot 1 is previously taught a painting operation corresponding to the shape of the work 4, and executes the painting work based on the teaching data.

A Coriolis mass flowmeter 13 is installed on the carriage 3. An inflow side paint tube 14 and an outflow side paint tube 15 are connected to the upper part of the mass flow meter 13.

The inflow side paint tube 14 is connected to a switching valve (both not shown) of a paint supply unit for supplying paint. The outflow-side paint tube 15 is mounted along the second arm 10 and connected to the paint gun 12.

Therefore, the paint pressure-fed from the paint supply unit passes through the inflow paint tube 14 and is supplied to the mass flowmeter 13 to measure the flow rate. Then, the paint flowing out from the mass flowmeter 13 is supplied to the coating gun 12 via the outflow side paint tube 15 and sprayed onto the work 4.

As described above, since the mass flow meter 13 is provided on the trolley 3, the mass flow meter 13 is moved from the coating gun 12 to the coating gun 12.
Is short, and the total length of the outflow side paint tube 15 can be considerably shortened. Therefore, the amount of paint remaining in the outflow-side paint tube 15 is reduced, and a small amount of paint and thinner are purged at the time of switching and waste is reduced.
Further, the responsiveness of the mass flowmeter 13 for measuring the flow rate with respect to the actual discharge amount of the sprayed paint is improved, and the delay in the flow rate measurement is reduced.

Here, the structure of the mass flowmeter 13 will be described.

As shown in FIGS. 3 and 4, the mass flow meter 13
Has a vibration type measurement unit 22 for measuring the Coriolis force proportional to the flow rate of the fluid to be measured.

As shown in FIG. 5, the measuring unit 22 includes
The sensor tube 25, a pair of vibrators 26a and 26b supported by the brackets 23 and 24, and a pickup 27.
a and 27b, which are housed in a cylindrical housing case 28. A disc-shaped bottom plate 29 is fitted and fixed to the lower opening of the storage case 28.

The bottom plate 29 is placed on the mounting surface 3a of the dolly 3, and the flange 30 projecting to the outer periphery of the lower end of the storage case 28 is fastened to the mounting surface 3a with bolts 31. As described above, in this embodiment, since the bottom surfaces of the storage case 28 and the bottom plate 29 are flat, they can be fastened directly to the mounting surface 3a without selecting a mounting location, so that if there is a planar portion, they can be easily mounted. it can.

A disk-shaped lid 32 is fitted in the upper opening of the storage case 28. Then, both ends of the sensor tube 25 and the upper ends of the columns 47 that support the vibrators 26a and 26b and the pickups 27a and 27b are fixed to the lid 32. Therefore, the measurement unit 22 is stored in the storage case 2
It is hung so that it may extend downward from the lid 32 that fits into the upper opening of 8.

As shown in FIGS. 3, 4 and 6, a vibration absorbing member 19 for absorbing external vibration is interposed between the upper opening 28a of the storage case 28 and the step portion 32a of the lid 32. ing. The vibration absorbing member 19 is an annular rubber tube and has an air spring structure having an air chamber 19a inside. The vibration absorbing member 19 is elastic due to the material itself and the pressure of the air in the air chamber 19a causes the storage case to move. The vibration propagated from 28 is elastically absorbed. Further, the vibration absorbing member 19 has a flange portion 19b protruding on the outer periphery thereof.
b is held in contact with the upper opening peripheral edge of the storage case 28.

Therefore, the measuring unit 22 is suspended so as to be elastically supported by the vibration absorbing member 19.

Further, the vibration absorbing member 19 is insert-molded so that a square plate nut 20 is embedded in the upper surface and the outer periphery thereof. Therefore, the fixing bolt 21 is attached to the lid 3
Hole 32c formed in the flange portion 32b of the second and the storage case 2
The vibration absorbing member 19 is inserted into the hole 28c formed in the outer periphery of the plate 8 and screwed into the plate-like nut 20 to be tightened.
It is fixed in a state of being sandwiched between the stepped portion 32a.

Thus, the upper opening 2 of the storage case 28
Since the vibration absorbing member 19 is interposed between the cover 8a and the lid 32, even if external vibration propagates to the storage case 28, the air chamber 19a of the elastic vibration absorbing member 19 functions as an air spring. Absorbs external vibration.

However, in this embodiment, the measuring unit 2
Since the second lid 32 is elastically supported by the vibration absorbing member 19, the vibration propagated to the storage case 28 is propagated to the measurement unit 22 housed in the storage case 28 while being insulated by the vibration absorbing member 19. Is prevented. Therefore, the measurement unit 22 can perform accurate flow rate measurement without being affected by external vibration as described later.

The storage case 28, bottom plate 29, lid 32
Are each made of synthetic resin, and are formed of, for example, polyacetal resin having excellent chemical resistance. Therefore,
Storage case 28 for storing the measurement unit 22, bottom plate 2
9. The weight of the lid 32 is reduced. The sensor tube 25 through which the fluid to be measured directly flows is made of stainless steel having excellent corrosion resistance.

Therefore, the measuring unit 22 is housed in the airtight container formed by the housing case 28 made of synthetic resin, the bottom plate 29, and the lid 32, and the vibration absorbing member 19 also functions as a seal member. It is possible to protect the sensor tube 25 from dew condensation while being protected from the outside atmosphere in the sealed space that is shielded from the outside. Further, a dry gas (for example, nitrogen gas) is enclosed in the storage case 28. As a result, accurate flow rate measurement can be performed without being affected by changes in temperature and humidity outside the storage case 28.

On the upper surface of the lid 32, the inflow port 34 to which the inflow side paint tube 14 is connected and the outflow side paint tube 1 are provided.
An outflow port 35 to which 5 is connected is bored. Joints 36 and 37 for fixing both ends of the sensor tube 25 are fitted to the inflow port 34 and the outflow port 35, and a seal is provided between each of the joints 36 and 37 and the inflow port 34 and the outflow port 35. It is sealed by members 38 and 39.

The sensor tube 25 is formed in a J shape when viewed from the rear of the painting robot 1, and has a straight pipe portion 25a on the inflow side and a straight pipe portion 25b on the outflow side that extend parallel to the hanging direction. And curved portions 25c and 25d curved in a U shape from the lower ends of the straight pipe portions 25a and 25b, and curved portions 25c and 25d.
It is composed of an inverted U-shaped connecting portion 25e for connecting and. or,
The upper end of the straight pipe portion 25a on the inflow side is fitted into a hole communicating with the inflow port 34. The straight pipe portion 25b on the outflow side has an outlet 35 at the upper end.
Fit into the hole communicating with the.

A connector box 43 is fixed to the upper surface of the lid 32, and a plurality of cords 44 from the vibrators 26a and 26b and the pickups 27a and 27b are drawn therein. The vibrators 26a and 26b have substantially the same structure as the electromagnetic solenoid, and the straight pipe portion 2 of the sensor tube 25 is used.
Magnets 26a ₁ provided at the lower ends of 5a and 25b,
26b ₁ and coils 26a ₂ and 26b ₂ for driving the magnets 26a ₁ and 26b ₁ in the Y direction orthogonal to the moving direction (X direction) of the carriage 3.

The pickups 27a and 27b have the same structure as the vibrators 26a and 26b, and the straight pipe portions 25a and 2b.
A cylindrical magnet 27a provided in the middle portion of 5b
A cylindrical coil 27a ₂ , which generates a voltage corresponding to the relative displacement between the ₁ , 27b ₁ and the magnets 27a ₁ , 27b ₁ ,
27b ₂ and detects the displacement of the straight pipe portions 25a and 25b in the Y direction.

Reference numeral 45 is a first support plate, which is a straight pipe portion 25.
The upper end portion penetrates a and 25b and is fixed to the outer circumference of the straight pipe portions 25a and 25b by brazing or the like. Reference numeral 46 denotes a second support plate, which is a connection portion 25e and curved portions 25c and 25d.
It is mounted between and and is fixed so as to hold both ends of the connecting portion 25e.

Therefore, when the lower ends of the straight pipe portions 25a, 25b are vibrated by the vibrators 26a, 26b, the straight pipe portion 25
a and 25b use the first support plate 45 as a fulcrum, and the curved portion 2
5c and 25d vibrate in the Y direction with the second support plate 46 as a fulcrum. As described above, the straight pipe portions 25a and 25b of the sensor tube 25 vibrate in the horizontal direction orthogonal to the external vibration in the vertical direction, and thus are not easily affected by the external vibration.

The pickups 27a and 27b detect horizontal displacement (Y direction) due to the Coriolis force proportional to the flow rate in the vibrating straight pipe portions 25a and 25b. The displacement of the straight pipe portions 25a and 25b is accurately detected according to the flow rate.

Reference numeral 47 denotes the sensor tube 25 and the vibrator 2
6a, 26b, and a column that supports the pickups 27a, 27b, the upper end of which is fixed to the lid 32 and the lower end of which is extended in the hanging direction. The lower end of the column 47 is a free end separated from the bottom plate 29 so that external vibration does not propagate through the bottom plate 29.

When measuring the flow rate, as described above, the vibrator 26a,
26b vibrates the straight pipe portions 25a and 25b of the sensor tube 25 in the horizontal direction (Y direction), and a pair of straight pipe portions 25a and 25b
5b vibrates in the horizontal direction (Y direction) so as to approach or separate from each other. The paint as the fluid to be measured flows into the straight pipe portion 25a of the vibrating sensor tube 25 as described above, passes through the curved portion 25c, the connecting portion 25e, the curved portion 25d, and the straight pipe portion 25b, and is downstream from the outflow port 35. It flows out to the tube 15. A Coriolis force having a magnitude proportional to the flow rate is generated in the straight pipe portions 25a and 25b, and opposite Coriolis forces are generated on the inflow side and the outflow side.

This causes a time delay between the straight pipe portions 25a and 25b, which is detected as a phase difference between the output signal of the pickup 27a and the output signal of 27b. The details of the principle of flow rate measurement are the same as those disclosed in Japanese Patent Application Laid-Open No. 63-262526 previously filed by the same applicant, and therefore will not be repeated here.

However, the mass flowmeter 13 having the above structure
The vibration is propagated through the carriage 3.

However, in this embodiment, the measuring unit 2
Since 2 is suspended via the vibration absorbing member 19 of the air spring structure, the external vibration from the truck 3 is elastically caused by the air pressure of the air chamber 19a of the vibration absorbing member 19 and the elasticity of the vibration absorbing member 19 itself. Be absorbed. Therefore, the vibration due to the movement of the carriage 3 does not propagate to the measuring unit 22, and the vibration absorbing member 19 effectively insulates the external vibration.

Moreover, in this embodiment, even if the vertical component of the external vibration propagates to the storage case 28 and the bottom plate 29, the straight pipe portions 25a and 25b of the sensor tube 25 are horizontally vibrated perpendicular to the vibration component. The pickup 27a, 27
b is the straight pipe portion 25a due to the Coriolis force generated in the Y direction,
Since the displacement of 25b is detected, the flow rate can be measured with almost no influence of external vibration. Therefore, the mass flow meter 13 can accurately measure the flow rate even when installed on the moving carriage 3.

Furthermore, when the carriage 3 moves in the X direction, the mass flowmeter 13 receives acceleration in the same direction. However, as described above, the sensor tube 2 of the mass flowmeter 13
5 is provided so as to be vibrated in the Y direction, which is a direction orthogonal to the moving direction of the carriage 3, and therefore the pickup 2
7a and 27b detect the Coriolis force in the Y direction that is not affected by the acceleration accompanying the movement of the carriage 3.

Therefore, even if the mass flowmeter 13 is installed on the moving carriage 3 together with the painting robot 1, the amount of paint supplied can be accurately measured.

In the above embodiment, the mass flowmeter 13 having a configuration in which the sensor tube shape is bent in a J shape has been described as an example, but it goes without saying that the sensor tube shape is not limited to this.

FIG. 6 shows a modification of the present invention.

In the figure, the first arm 1 of the painting robot 1
The mass flowmeter 13 is installed on the upper surface 10 a of 0, and the mass flowmeter 13 is fixed to the first arm 10 by a fixing belt 51.

Since the mass flowmeter 13 has the vibration absorbing member 19 interposed between the upper opening 28a of the storage case 28 and the lid 32 as described above, the vibration caused by the rotating operation of the first arm 10 is stored. Even when propagating to the case 28, the air chamber 19a of the elastic vibration absorbing member 19 functions as an air spring to absorb external vibration.

That is, the measuring unit 22 is the vibration absorbing member 1
The vibration of the storage case 28 is prevented from propagating to the measurement unit 22 housed in the storage case 28, which is insulated by the vibration absorbing member 19 and is supported in a suspended state via 9. . Therefore, the measurement unit 22
The accurate flow rate measurement can be performed without being affected by the vibration associated with the rotation operation of the first arm 10.

Further, from the mass flow meter 13 to the coating gun 12
Since the distance to the coating gun 15 is shorter than that of the configuration of the above embodiment, the paint tube 15 drawn from the mass flowmeter 13 and connected to the coating gun 12 is significantly shortened, and the coating gun 1 is correspondingly shortened.
It is possible to measure the flow rate change of the paint depending on the turning on and off of No. 2 with good responsiveness.

Further, in the mass flowmeter 13, the storage case 28, the bottom plate 29, and the lid 32 are made of synthetic resin, respectively, as described above, and since they are made lightweight, they are attached to the first arm 10. Also does not hinder the turning motion of the first arm 10. Therefore, the strength of the first arm 10 is reinforced,
Alternatively, it is not necessary to upsize the drive motor that drives the first arm 10.

In the above embodiment, the mass flowmeter has been described as an example, but it may be used as a vibration type density meter.

Further, the shape of the sensor tube is not limited to the shape of the above-mentioned embodiment, and it goes without saying that a shape bent into a U shape or a shape extending linearly may be adopted.

In the above embodiment, the number of sensor tubes is 1.
Although the mass flowmeter configured as a book is used, it can be applied to a configuration in which a pair of sensor tubes are vibrated so as to come close to or away from each other as shown in, for example, Japanese Patent Application Laid-Open No. 1-136026. In that case, the external signal can be canceled, but it is needless to say that the excitation signal may be provided so as to be orthogonal to the moving direction of the carriage.

[0061]

As described above, according to the invention of claim 1,
Since a vibration absorbing member that absorbs external vibration is provided between the opening of the storage case and the support member, external vibration should propagate to the measurement unit that vibrates the sensor tube and measures the mass flow rate or density of the fluid to be measured. Can be prevented
Accurate measurement is possible without being affected by vibration.
Further, since the bottom surface can be directly attached to the mounting surface for mounting, the mounting work can be easily performed.

According to the second aspect of the present invention, the vibration absorbing member for absorbing external vibration is provided between the opening of the storage case and the support member, and the storage case is made of synthetic resin. Since it is not necessary to reinforce the movable part or increase the load of the driving part when it is attached to the movable part, it can be installed without selecting an installation place.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coating system to which an embodiment of a vibration measuring apparatus according to the present invention is applied.

FIG. 2 is a rear view of the painting robot.

FIG. 3 is a vertical cross-sectional view for explaining the configuration of the mass flow meter.

FIG. 4 is a vertical cross-sectional view of the mass flow meter as viewed from the back side.

FIG. 5 is a perspective view of a measurement unit.

FIG. 6 is a vertical cross-sectional view showing an enlarged main part of the present invention.

FIG. 7 is a perspective view of a modified example of the present invention.

[Explanation of symbols]

 1 Painting Robot 2 Moving Device 3 Cart 4 Work 5 Conveyor Device 6 Base 12 Coating Gun 13 Mass Flow Meter 14 Inflow Side Coating Tube 15 Outflow Side Coating Tube 19 Vibration Absorbing Member 25 Sensor Tube 26a, 26b Vibrators 27a, 27b Pickup 28 Storage Case 32 Lid 47 Support

Claims (2)

[Claims] 1. A measurement unit for measuring a mass flow rate or density of a fluid to be measured by vibrating a sensor tube through which the fluid to be measured passes, a support member for supporting the measurement unit, and the support member fitted in an opening. A vibration-type measuring device having a storage case that is assembled to store the measurement unit, wherein a vibration absorbing member that absorbs external vibration is provided between the opening of the storage case and the support member. Vibration type measuring device. 2. A measuring unit for vibrating a sensor tube through which the fluid to be measured passes to measure the mass flow rate or density of the fluid to be measured, a supporting member for supporting the measuring unit, and the supporting member fitted in the opening. A vibration-type measuring device having a storage case that is assembled to store the measurement unit, wherein a vibration absorbing member that absorbs external vibration is provided between the opening of the storage case and the support member, A vibration-type measuring device, characterized in that the case is made of synthetic resin.